Portion of a refrigerator



FIG. 1 is a front perspective view of a portion of a refrigerator showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a right side view thereof; and,

FIG. 5 is a left side view thereof.

The broken lines shown in the drawing disclosure are for illustrative purposes only and form no part of the claimed design. The bottom view of the portion of the refrigerator forms no part of the claimed design. 

The ornamental design for a portion of a refrigerator, as shown and described. 